/*

 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.experimental.bytecode;

import java.lang.invoke.MethodHandles;

import java.lang.invoke.MethodHandles.Lookup;

import java.lang.reflect.Field;

import java.lang.reflect.Method;

import java.nio.ByteBuffer;

import java.util.Arrays;

import java.util.HashMap;

import java.util.Map;

import java.util.function.Consumer;

import java.util.function.ToIntFunction;

public class IsolatedMethodBuilder extends MethodBuilder<Class<?>, String, Object[]> {

    public IsolatedMethodBuilder(Lookup lookup, String name, String type) {

        super(null, name, type, new IsolatedMethodPoolHelper(lookup), null);

    }

    static class IsolatedMethodPoolHelper implements PoolHelper<Class<?>, String, Object[]> {

        Map<Object, Integer> constants = new HashMap<>();

        Lookup lookup;

        private IsolatedMethodPoolHelper(Lookup lookup) {

            this.lookup = lookup;

        }

        @Override

        public int putClass(Class<?> symbol) {

            return putIfAbsent(symbol);

        }

        @Override

        public int putFieldRef(Class<?> owner, CharSequence name, String type) {

            try {

                Field f = owner.getDeclaredField(name.toString()); //TODO: we should unreflect for a var handle

                return putIfAbsent(lookup.unreflectGetter(f));

            } catch (Throwable ex) {

                ex.printStackTrace();

                return -1;

            }

        }

        @Override

        public int putMethodRef(Class<?> owner, CharSequence name, String type, boolean isInterface) {

            try {

                Method m = owner.getDeclaredMethod(name.toString()); //we should unreflect according to method vs. constructor

                //and static vs. private etc.

                return putIfAbsent(lookup.unreflect(m));

            } catch (Throwable ex) {

                ex.printStackTrace();

                return -1;

            }

        }

        @Override

        public int putInt(int i) {

            return putIfAbsent(i);

        }

        @Override

        public int putFloat(float f) {

            return putIfAbsent(f);

        }

        @Override

        public int putLong(long l) {

            return putIfAbsent(l);

        }

        @Override

        public int putDouble(double d) {

            return putIfAbsent(d);

        }

        @Override

        public int putString(String s) {

            return putIfAbsent(s);

        }

        @Override

        public int putInvokeDynamic(CharSequence invokedName, String invokedType, Class<?> bsmClass, CharSequence bsmName, String bsmType, Consumer<StaticArgListBuilder<Class<?>, String, Object[]>> staticArgs) {

            return 0; //???

        }

        @Override

        public int putDynamicConstant(CharSequence constName, String constType, Class<?> bsmClass, CharSequence bsmName, String bsmType, Consumer<StaticArgListBuilder<Class<?>, String, Object[]>> staticArgs) {

            return 0; //???

        }

        @Override

        public int putHandle(int refKind, Class<?> owner, CharSequence name, String type) {

            return 0; //???

        }

        @Override

        public int putMethodType(String s) {

            return 0; //???

        }

        @Override

        public int putUtf8(CharSequence s) {

            return putIfAbsent(s);

        }

        @Override

        public int putType(String s) {

            return putIfAbsent(s);

        }

        @Override

        public int size() {

            return constants.size();

        }

        @Override

        public Object[] entries() {

            return constants.keySet().toArray();

        }

        int putIfAbsent(Object o) {

            int nextIndex = constants.size() + 1;

            Object res = constants.putIfAbsent(o, nextIndex);

            return res == null ?

                    nextIndex : (Integer)res;

        }

    }

    public Object[] entries() {

        return poolHelper.entries();

    }

    @Override

    public byte[] build() {

        byte[] arr = super.build();

        int codelength_offset = 2 + 2 + 2 + 2 +

                2 + 4 + 2 + 2;

        int code_offset = codelength_offset + 4;

        int length = ByteBuffer.wrap(arr).getInt(codelength_offset);

        byte[] opcodes = new byte[length];

        System.arraycopy(arr, code_offset, opcodes, 0, length);

        return opcodes;

    }

    public static void main(String[] args) {

        IsolatedMethodBuilder imb =  new IsolatedMethodBuilder(MethodHandles.lookup(), "foo", "(java/lang/String;)I");

        imb.withCode(C ->

                    C.aload_0()

                     .invokevirtual(String.class, "length", "()I", false)

                     .ireturn());

        byte[] opcodes = imb.build();

        System.out.println(Arrays.toString(opcodes));

    }

}